Fluid-pressure hammer



Feb. 15 1927.

' 1,617,969 l E; W. STEVENS FLUID PRESSURE HAMMER Filed May 1'. 1922 3 sheets-sheet 1 Feb. 15 1927.

E. w. STEVENS FLUID PRESSURE HAMMER Filed May l, 1922 5 Sheets-Sheet 2 um, m

amm, wm m 5mm,

1,617,969 Ev; w. STEVENS FLUID PRESSURE HAMMER Feb. 15, 1927.

Filed May 1 1922 s sheets-sheet 5 fraz/@W75 Y aLw-Md W/'mwg Patented Feb. 15,1927.

' EDWARD w. sTEvENs, oF DE'rnorr, MiCHiGAN, AssieNon fro cnicAGo PNEUMATIC Toor. ooivirANY, or NEW Yonai, N. Y., A oonronA'rIoN V0E, NEW JERSEY.

FLUID-RESSURE Application filed May l,

My invention relates to a Huid presssurey With the above and incidental objects 1n View, the invention consists in certain novel features of construction and combination of parts, the essential elements whereof are recited in the appended claims and a preferred form of embodiment of which is described in. detail hereinafter and illustrated in full. in the accompanying drawings, which form:-

part of this specification.

' Of said drawings, Fig. 1 is a sectional elevation of a hammer, embodying myy invention and showing the piston in an intermediate position during its forward stroke t0 deliver the blow upon the rivet set; Fig. 2

is a similar view but showing the piston and valve in changed position at the time of the delivery of the piston blow; Figs. 3 and 4L y are enlarged. sectional views, similar to Figs.

1 and 2, respectively, with the forward endy of the cylinder broken away; Fig. 5 isan. elevation ofthe rear end of the valve case;

Fig. 6 is an elevation of the forward end of the valve case'with the lid removed; Figi'y is a sectional elevation through` the body of the valve case; Fig. 8 is an elevation of the rearl end of the lid of the valve case; Fig.l 9 is a section on the line 9 9 of Fig. 8; Fig. 10 is an'elevation of the forward end of the lid of the valveA case; Figs. 11 and 12 are sections on the correspondingly indicated section lines of Fig. 9; Fig. 13 is an elevation of the rear end of the cylinder in which the piston reciprocates, and Fig. 11i is a side elevation of the tubular valve.

Referring to the particular embodiment Vof my invention, as shown herein, the same is a pneumatic riveting hammer andv I will proceed to describe itin connection with such particular type of hammer without being limited specifically thereto.

In general, the hammer comprises the cylinder 15, having the longitudinal piston chamber 16, a grasping handle 17, (shown broken away in the drawings) secured to the rear end of the cylinder in a well-known 1.922. Serial No. 557,550.

manner; a piston 18 reciprocable in the piston cylinder; valve mechanism,kincluding.

a valve 19v and a case or block 20,witha lid or covery 21, and a rivet set 22 inserted in the The air under forward end of the cylinder. pressure admitted through the grasping handle is controlled by` the main valve 19 Vwhich governs the admission and exhaust of air to and from opposite ends of the piston chamber as required 'for the reciprov i Y 65 V cations of the piston.

'The valve case, which is substantially a] cylindrical block provided with the lnecessary ports and passages, is contained within an enlarged counterbore .in the rearward end of the cylinder.V This case comprises the case proper or body 2O and| the lid or coverV 21. They case has a central bore within The bore ofv which fthe piston reciprocates. the lid 21 is slightly larger than the bore yinthe body 2() so as ,to receive the valve 19 which is tubular in general formation and coincident with the regular bore of the valve case and piston cylinder, 'so that the piston also reciprocates through the valve. Thev valve case and itslid have a series of ports Aand passagesl governed by the val-ve 19, by reason of the annular grooves and ribs or, enlargements of different diameters formed thereon. rIhese ports and :passages andy the particular vformation of the val-ve will be described, as I now proceedto vtrace the course of vthe aki-r under pressure through the hammer during a cycle of operation of Y the piston. Y l i In Figs. 1 and 3, the piston is beingdriven down on 'its forward stroke andis shown in an intermediate position. The air lpassing handle 17 enters the annular chamber 23,

case, and passes throughinclined ports25y lthroughy theVv passage 24 in the graspingV in the valvev case and thence through the r annular groove 26 in the valve case into the piston cl1amber.` The rear end of the piston, in these views, has cleared and uncovered the groove 26, so that the live air is admitted directly intothe piston cylinder behind the piston afterA the latter has received an initialforward movement, as willl be explained later. Vith the valve in the position shown in these views, exhaust ports 27, whichl are here in the Vlid 21 of the los valve case, are closed or coveredby they forward end portion of the valve. Each of the exhaust ports 27 is formed by two overlapping and converging transverse bores, as best shown in Figs. 9, l() and 1l, and these portsA communicate with longitudinal passages 28 at 'thefforward end of which are transverse exhaust port's'29. The forward ends of the passages 28 are in registry or coincidence with the exhaust passages 30 (Fig. 13) in the cylinder which lead to the atmosphere in the usual way. The ports 27 areH the exhaust ports for the lrear end of the cylinder and the ports 29 are the exhaust ports for the front end of the cylinder and these ports communicate with the interiorY lWith the valve 19 in the position shown in Figs. 'l and 3, the air in of thevalve case.

front of the piston on its downward stroke isY driven forwardly and allowed to escape freely'through passages 32 in the cylinder wall and the vave case into 'the annular groove or chamber, formed between the lid 2l and lvalve 19 rearwardly of an annularv enlargement 3l of the valve 19, and thence through the port-s 29 and' passages 28 and 30 `to the atmosphere. -`When vthe'valve is in this position the poits`29 and the forward ends of the passages 32 lare uncovered by the annular enlargement 3l of the valve 19.

The piston on its forward or downward ystrolfe uncovers a restricted portV 34 which communicates with the piston chamber with the result that the air behind the piston enters said port and passes rearwardly through a passage 35 in the cylinder and lid 2l, augmenting the pressure Vtherein against the large pressure area 37 constituting the forward face or side of theannular enlargement 3l of the valve, an inclined port or passage 36 being inv communication with the passage 35 and a shallow groove 39 formed inthe corner of the counterbore in the lid 21. rlherforward end of the passage 35 inthe lid 2l'has a restricted portion 44 in 'co-incidence ,with a port 38l branching fromcne of the ports 25. An unrestricted or enlarged port 38 `(Fig. l) at the forward end'of the passage35 communicates with the piston chamber. Before the piston .uncovers the 'port 34 and covers the port 38 live air passes through the branch 33a, the passage 35 and port 38 into the forward end of the piston'v chamber, but the portion 44 of the passage 35 is so restricted that the volume of'air passing through it and into the rforward end of the piston cylinder is not sufficient to retard or interfere with the move-V ment of thepiston.- 'As soon as the port 38 is closed some of the live air behind the piston passes through the port 34 and into the passage 35 and this air together with the air passing through the port 44 builds up sufficient pressure against the pressure area 3'? on the enlargement 3l of the valve 19, toV move the valve to the position shown in Figs. 2 and 4, in opposition'to the pressure on 'the rear end or edge of the valve, thereby causing the valve to cover the groove26 and cut off the supply `of live air to the rear end of the piston chamber. The

constant admission of air through the port 44 to the passage 35 materially quiclrens the a predetermined size se as to provide between it and an Vannular rib 46, formed on the valve case, an annular passage 47 (Fig. 4) ofa predetermined capacity, nth .the

result that a limited `amount of live air will be admitted to the forward end of thepistony chamber, sufficient to move the piston rea-n.v

'Ga y wardly but not with any unnecessary force,

or such force as might possibly cause it to.v

strike the rear end of the piston'chambe'ij',

notwithstanding the vcushioning provision thereof, to be. explained later, it being under-` stood that the piston should be. returned with a lighter pressure than thatV requiredA i for its forward stroke.

It will be observed, by referring to Figs.

3, 4, 6 and 7, that the ,forward end of the K valve case body 2O has a forwardly extending annular flange 49 provided with recesses 50 which are adapted to'register with the rear ends of the passages 32, there being one rec-ess for each passage. .lhenVt-he valve is in'itsrearward position, shown in Fig. 4, the enlargement 3l of the valve'engages the forward edge of the flange 49 and partially covers the ends of the passages 32 but the recesses or openings 5() form ports permitting the live air to pass into and through the passages 32 to. theforward end of the piston to return the same. ltwill be understoodv that at the saine time thev periphery of the enlargement 3l of the valve covers and closesthe ports 29 but that the valve has uncovered the exhaustV ports 27 to permit escape of the air from the rear end of the piston chamber until the ports .2T A

arey covered by the rear end ofthe piston entering the forward end of 'the valve on its return stroke. ward position. by the live air admitted through the port 44 and passage 35 and to rlhe valve is held in its rear-- iasiaeee the piston, itdoes .not cause ,much pressure again'st-theltop or'rear' .face ofthe-'enlarge v ment .3l and .thewarfpressure onthe oppose site side `"ofthe"enlargement .is z'suflicien't 'to maintain the valve in'it's rearward position until the pressure-ofy air` compressed bythe piston, as willnowbe described, shifts the valve forwardly again :tothe positionjshown in Figs. land. j' y i `The piston continues upwardly or Vrearwardly unrestricted'until lit 'covers the express theair trapped by it, the valvecas thus constituting a cushionl chamber. As

i soonas', the reai' end Iof the piston enters the.

valvelitibegiiis yto Kcompress. the, air in the rear endof the piston chamber and'by the time the' ife'arfend offthe' pist/oli has reached Y the rear end of the valve the pressure exerted by the compressed air against the rear end 51 of the valve is suflicient to overcome the rpressure exerted against the pressure area 377011 the enlargement 31 of the valve,

whereupon the valve is shifted from the position shown in Figs. 2 and 4 to the position shown in Figs. l and 3. It is'obvious that piston reciprocable in said vpiston chamber,`

rthe rear` end of the piston chamber acts as a cushion forv the piston. A` passage 45 `communicates with the forward end of the cushion chamber and the annular chamber 23, livel air being admitted through this passage to give the piston its initial forward movement until its rear endhas passed the rear end Vof the valve on its forward i stroke, at which time the live air isl admitted through the passages 25 and groove 26 to the rear of the piston, as above described.v

Thiscompletes the cycle of operation.

It will be observed that'theonly commu- Vnicating passage extending through and from the valve body 20 to the lid 2l is that formed by the passages 38a and 35. This is highly desirable and importa-nt as it lends simplicity to the construction and minimizes the chance of leakage between these parts. Analigning pin 54 extends through an opening in the lid 2l and the forward end of the pin projects into a recess 52 in the cylinder, .while the rear end projects into a recess 53 in the body 20, for the purpose of properly aligning Vthe valve case in the cylinder.

I claim: Y

1. In a pneumatic hammer, the combination of a cylinder, having a Vpiston chamber, a Valve case, admission and exhaust ports and passages in said cylinder andcase, a

a valve controlling said ports and passages, means subJecting a pressure area of the valve .continuously to fluid pressure, means for permitting said pressure to, build up during at least apart of the movement of said piston in one direction, and means operating substantially c-oncomitantly withl said 'u last named pressure.

2. In a pneumatic hammer, the combina;

tion lofa cylinder, having a piston chamber., .a

valve case, admission and exhaust ports. and; passages in :said cylinder andvcase, Aa pistonl reciproc'abl'e insaid piston chamber, 'a .valve`4 .controlling.said-ports and passages, means: .p subjecting a. pressure area y'of the-valve con# -v tinuously tofluid pressure, means forfper-` -mitting said Apressure to build up duringat ,leastz-ea .part of the movement yof said piston Y in one direction, and means operating sub-v m'ean's `for augmentiiugI said- -stantially .f concomitantly with Vsaid' .lastname-l means :for augmenting saidl pressure,

thetwo `last named means being controlled-a4 Vvalve case comprising'a vbody and a lid with sure VHuid thereto to control the actuation Y of said valve.fv

4. In a pneumatic hammer, the combinationk of a cylinder having a piston chamber therein, a valve, a valve case at one end comprising a vbody and a lidrhaving but oneV v continuous air passage extending through them, the passage communicating directly with the motive fluid supplyand being uncontrolled by the valve, and admission and exhaust ports and passages in said case and cylinder controlled byl said valve.

5. In a pneumatic hammer, the'combination of'a cylinder, a piston therein, avalve case at one `end of the cylinderand having a lid provided with ports, such case and lid having a central bore through which the pist on reciprocates, recesses in the case registering with said ports, and a tub-ular valve in suchk case adapted to open said ports when the valve isin one position and v to close said ports except for said recesses` when in another position.

i 6. In a pneumatic hammer, the combinati-on of a cylinder, a piston therein, a valve case at one end of the cylinder and having a lid provided with ports, such case and lid having a central bore through which the piston reciprocates and the lid also having a counterbore therein, a flange on the case extending yinto said counterbore and.y pro-l vided with recesses in registry ywith said ports, and a tubular valve having an enlargement in said counterbore and adapted to uncoverv the ports .when in one position '41, Y 1 a Y 1,617,969v

Y position.y f

7. In apneuinatichammer, in combination,l a cylinder vhaving a. piston chamber, a piston reciprocable in saidV chamber, a valve 'case having'a 11d disposed at one end of said cylinder and defining a portion of the piston chamber, admission and exhaust fports and passages in said cylinder and said case, an imperforate .sleevefvalve Within said case controlling said ports and passages, said valve being arranged to be shifted in vone 'direction' by air-V compressedby the piston on its non-Working stroke, meansshifting said Valve'in the oppsite direction by built- V up pressure augmented at the proper instant by pressure fluid fromthe piston chamber comprisinga passage communicating with a `pressure area of vthe y valve an-d `having 20' pressure a fluid continuously admittedk thereto in limited amount and spaced piston con-V trolled ports controlling the Yexhausting ot' the passager to the piston ,chamber and the' admission of pressure Huidl totliepassage lfrom the piston chamber, said valve case and lid having cooperating vinterfitting arts recesses in the innermost of said )arts Y controlled by said valve registering with assaoes in said outermost aarts'for direct- 25 ing motive fluidA to 'drive the piston on its non-Working stroke, said valve being arranged to utilize the central borey of `said EDWARD W. sTEVENs i 

